Justin Visser
33a85cb720
Adjacency lives in slices, not maps, on purpose: Go randomises map iteration order between runs, and the engine's determinism guarantee needs every graph walk to visit neighbours in the same order. AddEdge mirrors networkx semantics (duplicates and self loops are no-ops) so the Holme-Kim port can lean on the same behaviour. Receiver names stay short per Go convention (g *Graph); everything else uses descriptive names.
27 lines
821 B
Go
27 lines
821 B
Go
package engine
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import "testing"
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// Determinism is a locked project decision: the same seed must always yield
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// the same stream, and different seeds must not collide. With fixed seeds
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// these assertions are exact, not probabilistic.
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func TestNewRandSameSeedSameStream(t *testing.T) {
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firstStream, secondStream := newRand(17), newRand(17)
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for draw := range 100 {
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first, second := firstStream.Float64(), secondStream.Float64()
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if first != second {
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t.Fatalf("draw %d: streams diverged: %v != %v", draw, first, second)
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}
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}
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}
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func TestNewRandDifferentSeedsDiffer(t *testing.T) {
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seededWith17, seededWith18 := newRand(17), newRand(18)
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for range 100 {
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if seededWith17.Float64() != seededWith18.Float64() {
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return // diverged, as expected
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}
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}
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t.Fatal("seeds 17 and 18 produced 100 identical draws")
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}
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